Pituitary Tumor Transforming Gene Research Articles

Protein Expression of PTTG1 as a Diagnostic Biomarker in Adrenocortical Carcinoma.

Adrenocortical carcinoma (ACC) has a poor prognosis and there is an unmet clinical need for biomarkers to improve both diagnostic and prognostic assessment. Pituitary-tumor transforming gene (PTTG1) has been shown to modulate cancer invasiveness and response to therapy. The potential role of PTTG1 protein levels in ACC has not been previously addressed. We assessed whether increased nuclear protein expression of PTTG1 distinguished ACCs from adrenocortical adenomas (ACAs). Patients with ACC or ACA were identified from prospective tissue banks at two independent institutions. Two tissue microarrays (TMAs) consisting of adrenal specimens from 131 patients were constructed and clinically annotated. Immunohistochemical analysis for PTTG1 and Ki-67 was performed on each TMA. TMA-1 (n=80) contained 20 normal adrenals, 20 ACAs, and 40 ACCs, and the validation, TMA-2 (n=51), consisted of 10 normal adrenals, 14 ACAs, and 27 ACCs. On TMA-1, nuclear staining of PTTG1 was detected in 12 (31%) ACC specimens, while all ACAs and normal adrenal glands were negative for PTTG1. On TMA-2, 20 (74%) of the ACC tumors demonstrated PTTG1 nuclear staining of PTTG1, and 13 (93%) ACA and 4 (44%) normal adrenal glands were negative for PTTG1. ACC tumors with increased PTTG1 protein staining had a significantly higher Ki-67 index (p<0.001) than those with lower levels of PTTG1. Increased nuclear protein expression of PTTG1 was observed in malignant adrenal tumors. PTTG1 correlated with Ki-67 in two independent TMAs. PTTG1 is a promising biologic marker in the evaluation of adrenal tumors.

RNF20 Suppresses Tumorigenesis by Inhibiting the SREBP1c-PTTG1 Axis in Kidney Cancer.

Elevated lipid metabolism promotes cancer cell proliferation. Clear cell renal cell carcinoma (ccRCC) is the most common subtype of kidney cancers, characterized by ectopic lipid accumulation. However, the relationship between aberrant lipid metabolism and tumorigenesis in ccRCC is not thoroughly understood. Here, we demonstrate that ring finger protein 20 (RNF20) acts as a tumor suppressor in ccRCC. RNF20 overexpression repressed lipogenesis and cell proliferation by inhibiting sterol regulatory element-binding protein 1c (SREBP1c), and SREBP1 suppression, either by knockdown or by the pharmacological inhibitor betulin, attenuated proliferation and cell cycle progression in ccRCC cells. Notably, SREBP1c regulates cell cycle progression by inducing the expression of pituitary tumor-transforming gene 1 (PTTG1), a novel target gene of SREBP1c. Furthermore, RNF20 overexpression reduced tumor growth and lipid storage in xenografts. In ccRCC patients, RNF20 downregulation and SREBP1 activation are markers of poor prognosis. Therefore, RNF20 suppresses tumorigenesis in ccRCC by inhibiting the SREBP1c-PTTG1 axis.

PTTG1 cooperated with GLI1 leads to epithelial-mesenchymal transition in esophageal squamous cell cancer.

Pituitary tumor-transforming gene-1 (PTTG1) could acquire its metastasis-promoting effects via inducing epithelial-mesenchymal transition (EMT). However, its role and mechanism in EMT in esophageal squamous cell cancer (ESCC) had not been clearly elucidated. Here, we demonstrated that PTTG1 was overexpressed in ESCC cell lines and tissues especially those with lymph node metastasis. Down regulation of PTTG1 levels dampened the ESCC cells invasion, migration, proliferation ability and colony formation in vitro and inhibited the growth of mouse xenograft model of ESCC cells in vivo. In addition, our in vitro and in vivo experiments consistently showed that decreased PTTG1 led to the inhibition of EMT process. Glioma-associated oncogene homolog1 (GLI1), a key factor in HH-GLI signaling pathway, was also overexpressed in ESCC cells and tissues. Mechanistic studies demonstrated that decreased PTTG1 mitigated the expression levels of GLI1 in vitro and in vivo and ChIP assay also indicated that PTTG1 cooperated with GLI1 by binding to its promoter. Furthermore, overexpression of GLI1 rescued the EMT inhibited by down regulation of PTTG1 in vitro. Together, these data suggested that PTTG1 promoted the invasion ability of ESCC cells via EMT, more important, PTTG1 participated in EMT via activating the expression of GLI1 in ESCC. PTTG1 could be a candidate biomarker for defining ESCC metastasis and useful target for therapy.

Functional consequences of the first reported mutations of the proto-oncogene PTTG1IP/PBF.

Pituitary tumor-transforming gene 1-binding factor (PTTG1IP; PBF) is a multifunctional glycoprotein, which is overexpressed in a wide range of tumours, and significantly associated with poorer oncological outcomes, such as early tumour recurrence, distant metastasis, extramural vascular invasion and decreased disease-specific survival. PBF transforms NIH 3T3 fibroblasts and induces tumours in nude mice, while mice harbouring transgenic thyroidal PBF expression show hyperplasia and macrofollicular lesions. Our assumption that PBF becomes an oncogene purely through increased expression has been challenged by the recent report of mutations in PBF within the Catalogue of Somatic Mutations in Cancer (COSMIC) database. We therefore sought to determine whether the first 10 PBF missense substitutions in human cancer might be oncogenic. Anisomycin half-life studies revealed that most mutations were associated with reduced protein stability compared to wild-type (WT) PBF. Proliferation assays narrowed our interest to two mutational events which significantly altered cell turnover: C51R and R140W. C51R was mainly confined to the endoplasmic reticulum while R140W was apparent in the Golgi apparatus. Both C51R and R140W lost the capacity to induce cellular migration and significantly reduced cell invasion. Colony formation and soft agar assays demonstrated that, in contrast to WT PBF, both mutants were unable to elicit significant colony formation or anchorage-independent growth. However, C51R and R140W retained the ability to repress radioiodide uptake, a functional hallmark of PBF. Our data reveal new insight into PBF function and confirm that, rather than being oncogenic, mutations in PBF are likely to be passenger effects, with overexpression of PBF the more important aetiological event in human cancer.

Berberine Inhibits Uterine Leiomyoma Cell Proliferation via Downregulation of Cyclooxygenase 2 and Pituitary Tumor-Transforming Gene 1.

We previously demonstrated that berberine (BBR) inhibits cell proliferation and induces apoptosis in a human uterine leiomyoma (UtLM) cell line but does not demonstrate a significant cytotoxic effect in a normal human uterine smooth muscle (UtSM) cell line. However, the mechanisms of this inhibition are unclear. Of note, cyclooxygenase 2 (COX2) and pituitary tumor-transforming gene 1 (PTTG1) are overexpressed in human uterine leiomyomata and are involved in the pathogenesis of uterine fibroids (UFs). We found that COX2 and PTTG1 were overexpressed in UtLM and that BBR decreased COX2 and PTTG1 expression in UtLM cells. Our data support that UtLM and UtSM are immortalized cell lines without phenotypic alterations from parental cell types and suggest that COX2 and PTTG1 are molecular targets for BBR. However, studies in these cell lines may not reveal all activities of BBR in vivo, and we therefore proceeded to test in this report the antitumor effects of BBR in an UF nude mouse xenograft model. When UF nude mice were killed at 7 weeks, tumor weight in controls was 45 ± 7 mg versus 20 ± 3 mg ( P < .05) in the low-dose (5 mg/kg) and 7 ± 3 mg ( P < .01) in the high-dose (10 mg/kg) BBR groups, respectively. Expression of proliferation markers, cell cycle-related genes, and UF-related genes was downregulated in tumors. No unusual behavioral changes and no signs of kidney or liver damage were observed in the animals with BBR treatment. In conclusion, our data suggests that (a) COX2 and PTTG1 are molecular targets for BBR and (b) BBR is potentially an effective and safe anti-UF agent.

Abstract 5551: Systematic analysis of novel noncoding genes associated with poor prognostic pathways in lung adenocarcinoma

Abstract Non-coding genes are shown to play important roles in cancer progression with potential for serving as theranostic biomarkers. However, there is still a lack of studies to predict the biological roles of novel non-coding genes in tumorigenic pathways and associations with patient survival. Lung adenocarcinoma (LUAD) is the predominant histological subtype of lung cancer, which is the leading cause of cancer death. Nowadays, target therapies have improved LUAD patients’ survival about 6-12 months, but limited improvement of long-term survival, suggesting that discovering new therapeutic targets are important. Therefore, here we applied weighted correlation network analysis (WGCNA) to cluster highly correlated genes of transcriptomic data to accurately investigate the functions of non-coding genes with poor prognosis in lung adenocarcinoma (LUAD). We discovered a total of 627 differential expressed coding and non-coding genes (DEGs) from 6 transcriptomic datasets derived from LUAD patients with survival information. By using WGCNA, we discovered 6 non-coding candidates (PTTG3P, MIR497HG, HSP078, TBX5-AS1, LOC100506990, and C14orf64) and their core networks of DEGs, which were highly associated with patient survival and clustered in modules functioning in cell cycle and migration. We noticed that a previously known processed pseudogene, PTTG3P (Pituitary Tumor-transforming Gene 3), is highly correlated with poor survival and associated with mitosis of the cell cycle. Up-regulated PTTG3P expression in LUAD was in silico validated of RNA-seq data from TCGA compared to normal lung tissues (fold-change= 2, p-value&amp;lt; 0.0001) and associated with poor 5-year survival rates (HR= 1.83, p-value= 0.012). We further confirmed PTTG3P is highly expressed and associated with poor survival outcome of LUAD patients in Taiwan (HR= 1.75, p-value= 0.037) with RNA-ISH experiments. To examine the coding potential of pseudogene PTTG3P, we found that PTTG3P might encode a consensus 21 kDa novel polypeptide from a single exon by using various prediction programs of coding potential. Ectopic expression of PTTG3P in lung cancer cells indicated that PTTG3P protein can be detected resulted in shortening the process of metaphase to anaphase in cell cycle progression and promotion of cell proliferation. Knockdown experiments of PTTG3P further reversed aforementioned experiments. Together, we established a powerful and systematic strategy for functional classification of non-coding genes in association with poor prognosis of LUAD patients. We revealed that commonly annotated and processed pseudogenes defined as non-coding genes for lacking of introns and promoter regions could still be translated into functional polypeptides. We found processed pseudogene PTTG3P can be translated to a protein, which might play an important role in predicted function of mitosis and impact on poor survival in LUAD patients. Citation Format: Jou-Ho Shih, Yuh-Shan Jou. Systematic analysis of novel noncoding genes associated with poor prognostic pathways in lung adenocarcinoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5551. doi:10.1158/1538-7445.AM2017-5551

Identification of peptide-mediated interactions between human PTTG and SH3 domains in pALL gene expression profile

Human pituitary tumor-transforming gene (PTTG) plays an essential role in the development and progression of pediatric acute lymphoblastic leukemia (pALL). PTTG has two SH3-binding peptide motifs that can be recognized by a variety of SH3-containing proteins in the pALL through peptide-mediated interactions. In this study, the gene expression profile of pALL was examined in detail by integrating computational modeling and experimental assay, aiming to identify those potential partner proteins of human PTTG. The binding potency of domain candidates to peptide motifs was ranked using knowledge-based scoring and fluorescence titration. A number of SH3 domains found in a variety of pALL proteins were identified as potent binders with moderate or high affinity for PTTG. It is revealed that the PTTG peptide motifs show different affinity profiles for various candidate proteins, indicating that the PTTG selectivity is optimized across pALL gene expression space. The PTTG peptides were then mutated rationally to target the SH3 domains of identified partner proteins by competing with the native peptide motifs.

Integrated In Silico-In Vitro Identification and Characterization of the SH3-Mediated Interaction between Human PTTG and its Cognate Partners in Medulloblastoma.

The human pituitary tumor-transforming gene is an oncogenic protein which serves as a central hub in the cellular signaling network of medulloblastoma. The protein contains two vicinal PxxP motifs at its C terminus that are potential binding sites of peptide-recognition SH3 domains. Here, a synthetic protocol that integrated in silico analysis and in vitro assay was described to identify the SH3-binding partners of pituitary tumor-transforming gene in the gene expression profile of medulloblastoma. In the procedure, a variety of structurally diverse, non-redundant SH3 domains with high gene expression in medulloblastoma were compiled, and their three-dimensional structures were either manually retrieved from the protein data bank database or computationally modeled through bioinformatics technique. The binding capability of these domains towards the two PxxP-containing peptides m1p: 161LGPPSPVK168 and m2p: 168KMPSPPWE175 of pituitary tumor-transforming gene were ranked by structure-based scoring and fluorescence-based assay. Consequently, a number of SH3 domains, including MAP3K and PI3K, were found to have moderate or high affinity for m1p and/or m2p. Interestingly, the two overlapping peptides exhibits a distinct binding profile to these identified domain partners, suggesting that the binding selectivity of m1p and m2p is optimized across the medulloblastoma expression spectrum by competing for domain candidates. In addition, two redesigned versions of m1p peptide ware obtained via a structure-based rational mutation approach, which exhibited an increased affinity for the domain as compared to native peptide.

ShRNA-mediated knockdown of pituitary tumor transforming gene 1 (PTTG1): optimization of the effect on early osteoblast differentiation

ShRNA-mediated knockdown of pituitary tumor transforming gene 1 (PTTG1): optimization of the effect on early osteoblast differentiation

SiRNA-mediated silencing of bFGF gene inhibits the proliferation, migration, and invasion of human pituitary adenoma cells.

Human pituitary adenoma is one of the most common intracranial tumors with an incidence as high as 16.7%. Recent evidence has hinted a relationship between growth factors of pituitary or hypothalamic origin and proliferation of human pituitary adenoma cells. This study explores the effects of small interfering RNA-mediated silencing of basic fibroblast growth factor gene on the proliferation, migration, and invasion of human pituitary adenoma cells. Human pituitary adenoma tissues were collected to obtain human pituitary adenoma cells. The basic fibroblast growth factor silencing interference plasmid was constructed, and the human pituitary adenoma cells were transfected and assigned as basic fibroblast growth factor-small interfering RNA, negative control-small interfering RNA, and blank groups. The quantitative real-time polymerase chain reaction and Western blotting were carried out to detect the expression of basic fibroblast growth factor, pituitary tumor transforming gene, vascular endothelial growth factor, cluster of differentiation 147, and matrix metalloproteinase 9. Cell Counting Kit-8 assay was conducted to observe cell proliferation at 0, 24, 48, and 72 h. Flow cytometry was used to determine cell cycle. Transwell and scratch test were applied to detect the invasion and migration of pituitary adenoma cells. Protein kinase C activity was detected. In comparison with the blank group, the basic fibroblast growth factor-small interfering RNA group showed reduced messenger RNA and protein expression of basic fibroblast growth factor, reduced cell viability at 24, 48, and 72 h, increased cells in G0/G1 stage, declined cells in S and G2/M stages, decreased number of cell migration, shortened migrating distance, reduced protein kinase C activity, and decreased expression of pituitary tumor transforming gene, vascular endothelial growth factor, cluster of differentiation 147, and matrix metalloproteinase 9. However, the negative control-small interfering RNA group had no evident differences in basic fibroblast growth factor expression, cell viability, cell cycle, number of cell migration, migrating distance, protein kinase C activity, and expression of pituitary tumor transforming gene, vascular endothelial growth factor, cluster of differentiation 147, and matrix metalloproteinase 9 compared with the blank group. The study provides evidence that small interfering RNA-mediated silencing of basic fibroblast growth factor gene inhibits the proliferation, migration, and invasion of human pituitary adenoma cells.

Berberine regulates the protein expression of multiple tumorigenesis-related genes in hepatocellular carcinoma cell lines

BackgroundHepatocellular carcinoma (HCC) is the seventh most common malignancy and the third leading cause of cancer-related death worldwide with an extremely grim prognosis. Berberine (BBR) has been found to inhibit proliferation of human HCC cells, although the underlying mechanism(s) are unclear.MethodsProtein expression was detected by Western blots. Cell viability was determined by using the CellTiter Assay kit.ResultsWe confirm that BBR treatment inhibits HepG2, Hep3B, and SNU-182 cell viability, and suggest that it regulates this proliferation via the modulation of multiple tumorigenesis-related genes protein expression. BBR treatment up-regulated protein expression of tumor suppressor genes, including Kruppel-like factor 6 (KLF6), activating transcription factor 3 (ATF3) and p21, while down-regulating the expression of selected oncogenes, including E2F transcription factor 1 (E2F1) and pituitary tumor transforming gene 1 (PTTG1). The specific extracellular signal–regulated kinases 1/2 (ERK1/2) inhibitor, PD98059, partially inhibited BBR effects including reduction of cell viability, and up-regulation of KLF6 and ATF3 expressions; although, PD98059 did not alter the down-regulation of E2F1 and PTTG1 expression by BBR.ConclusionsOur results suggest that BBR inhibits HCC cell viability by modulating multiple tumorigenesis-related genes, and that up-regulation of tumor suppressor genes by BBR is in part the result of ERK1/2 action. The results of this study augment our understanding of the mechanisms underlying the effect of BBR on hepatocellular cancers and provide further evidence as to the biological plausibility of this agent’s role in the treatment of these malignancies.

MicroRNA-524-5p Functions as a Tumor Suppressor in a Human Pituitary Tumor-Derived Cell Line.

Clinical nonfunctional pituitary adenomas (NFAs) account for about 40% of pituitary adenomas with almost no clinically relevant hormonal symptoms. Increasing evidence shows that many microRNAs are involved in the development and progression of pituitary adenomas. MicroRNA-524-5p (miR-524-5p) has been reported to cause characteristic alterations in various tumors. However, the functional importance of miR-524-5p in NFAs remains unknown. The aim of this study was to explore the effects of overexpressing miR-524-5p on the proliferation, migration, invasion, and tumorigenicity of pituitary-derived folliculostellate (PDFS) cells using lentiviral transfection. Interestingly, the results showed that overexpressing miR-524-5p downregulated pituitary tumor-transforming gene 1 (PTTG1) binding factor (PBF) expression at both mRNA and protein levels and significantly attenuated cell proliferation, clonogenicity, migration, and invasion in vitro. Moreover, enhancing miR-524-5p blocked tumor growth in a nude mouse xenograft model in vivo. These findings suggest that miR-524-5p appears to play a critical role in the regulation of biological properties of PDFS cells, and may represent a potential therapeutic target for NFAs.

Expression of cell cycle regulators and biomarkers of proliferation and regrowth in human pituitary adenomas.

The pathogenesis of pituitary adenomas (PA) is complex. Ki-67, pituitary tumour transforming gene (PTTG), vascular endothelial growth factor (VEGF), cyclin D1, c-MYC and pituitary adenylate cyclase-activating peptide (PACAP) protein expression were analysed and correlated with tumour and patient characteristics. 74 pituitary tumour samples (48 non-functional PA, 26 functional PAs); Immunohistochemical analysis of protein expression, retrospective analysis of MR images and in vitro analysis of octreotide treatment was carried out on GH3 cells. PTTG expression was negatively associated with age and positively with PA size, regrowth and Ki-67 index. Cyclin D1 correlated with Ki-67 and tumour size. c-MYC negatively correlated with size of tumour and age; and correlated with PTTG expression. Somatostatin analogue treatment was associated with lower Ki-67, PTTG and Cyclin D1 expression while T2 hypointense PAs were associated with lower PTTG, cyclin D1, c-MYC and Ki-67. In vitro analyses confirmed the effect of somatostatin analogue treatment on Pttg and Cyclin D1 expression. Interesting and novel observations on the differences in expression of tumour markers studied are reported. Correlation between Ki-67 expression, PTTG nuclear expression and recurrence/regrowth of PAs, emphasizes the role that Ki-67 and PTTG expression have as markers of increased proliferation. c-MYC and PTTG nuclear expression levels were correlated providing evidence that PTTG induces c-MYC expression in PAs and we propose that c-MYC might principally have a role in early pituitary tumorigenesis. Evidence is shown that the anti-proliferative effect of somatostatin analogue treatment in vivo occurs through regulation of the cell cycle.

The clinical value and biological function of PTTG1 in colorectal cancer

Pituitary tumor transforming gene-1 (PTTG1) has been suggested to serve as an oncogene in several types of human tumors, but little is known about the biological function of PTTG1 in colorectal cancer. PTTG1 mRNA and protein expressions in colorectal cancer tissues and cell lines were measured by qRT-PCR, western blot or immunohistochemistry. The association between PTTG1 protein expression and clinicopathological features was analyzed. The function of PTTG1 on colorectal cancer cell proliferation and metastasis were explored through MTT, colony formation, migration and invasion assays. In our results, PTTG1 mRNA and protein expressions were increased in colorectal cancer tissues and cell lines compared with normal colonic tissues and colon epithelial cell line. PTTG1 overexpression positively associated with clinical stage, T classification, N classification, M classification and differentiation. The univariate and multivariate analyses suggested PTTG1 overexpression was an independent poor prognostic factor for colorectal cancer patients. The in vitro experiments showed knocking down PTTG1 inhibited colorectal cancer growth and metastasis. In conclusion, PTTG1 is an independent prognostic factor and acts as an oncogene in colorectal cancer.

Study on miRNAs' expression for the invasion of pituitary adenomas.

To explore the possible invasive effect of four microRNAs in invasive pituitary adenomas. Based on our previous studies, several in silico algorithms, and relative literatures, 30 Han Chinese patients with invasive pituitary adenomas and 30 with non-invasive pituitary adenomas were involved in this research. The proteins related to invasion underwent immunohistochemical staining, including basic fibroblast growth factor (FGF2), pituitary tumor transforming gene (PTTG), cyclin B1 (CCNB1), survivin, focal adhesion kinase (FAK), and microvessel density (MVD). To validate the effect of microRNAs, miR-24, miR-93, miR-126, and miR-34a were chosen as possible targets for the aforementioned proteins with four in silico algorithms. All microRNAs tests were performed using quantitative real-time polymerase chain reaction (qPCR). In our study, FGF2, FAK, PTTG, CCNB1, and MVD were overexpressed in the invasive group compared with the non-invasive group, while an increase in the expression of survivin in the invasive group did not achieve statistical significance. This paper reviewed the literature, and four microRNAs involving invasion were selected for study: miR-24, miR-34a, miR-93, and miR-126. Under-expression of miR-24, miR-34a, and miR-93 was significant in the invasive group, while a decrease of miR-126 expression in the invasive group did not achieve statistical significance. FGF2, PTTG, CCNB1, survivin, FAK, and MVD proteins of pituitary adenoma showed strong expression in invasive tumors. Furthermore, miR-24, miR-93, miR-34a, and miR-126 were under-expressed in invasive Pituitary adenomas compared with non-invasive ones. The results indicated some relationship between the miRNA and protein expression during the pituitary invasion process.

PTTG1 regulated by miR-146a-3p promotes bladder cancer migration, invasion, metastasis and growth.

Pituitary tumor-transforming gene 1 (PTTG1) is identified as an oncogene, and overexpresses in many tumors. However, the role of PTTG1 in bladder cancer (BC) hasn't yet been characterized well. In this study, we showed the expression of PTTG1 mRNA and protein were both significantly increased in BC tissues and cells. The PTTG1 protein levels were positive correlated with increased tumor size, tumor–node–metastasis (TNM) stage, lymphatic invasion and distant metastasis of BC. PTTG1 knockdown dramatically suppressed the migration, invasion, metastasis and growth, and induced senescence and cell-cycle arrest at G0/G1 phase of BC cells. We further identified PTTG1 was the direct target of miR-146a-3p through using target prediction algorithms and luciferase reporter assay. miR-146a-3p was low expressed and negatively correlated with PTTG1 levels in BC tissues and cells. miR-146a-3p overexpression inhibited migration, invasion, metastasis and growth, and induced senescence of BC cells. Rescue experiment suggested ectopic expression of miR-146a-3p and PTTG1 suppressed migration, invasion and induced cell cycle arrest and senescence of BC cells compared to PTTG1 overexpression, confirming miR-146a-3p inhibited BC progression by targeting PTTG1. In summary, our study found miR-146a-3p/PTTG1 axis regulated BC migration, invasion, metastasis and growth, and might be a targets for BC therapy.

Benzene and 2-ethyl-phthalate induce proliferation in normal rat pituitary cells

PurposeEndocrine disruptors are known to modulate a variety of endocrine functions and increase the risk for neoplasia. Epidemiological data reported increased prevalence of pituitary tumors in high industrial areas while genotyping studies showed that mutations in the aryl hydrocarbon receptor (AhR) interacting protein (AIP)—chaperone to the dioxin ligand AhR—gene are linked to predisposition to pituitary tumor development. Aim of the present study was to establish whether endocrine pollutants can induce cell proliferation in normal rat pituitary cells.MethodsPituitary primary cultures were incubated with 250, 650 and 1250 pM benzene or 2-ethyl-phthalate for up to 96 h and viability, energy content and cell proliferation assessed. Expression of pituitary tumor transforming gene (PTTG), cyclin D1 (Ccnd1), AhR and AIP was quantified by RT-qPCR.ResultsIncubation with benzene or 2-ethyl-phthalate increased viability and energy content in pituitary cells. The endocrine disruptors also increased cell proliferation as well as Ccnd1 and PTTG expression. Increased AhR and AIP expression was observed after incubation with the two pollutants.ConclusionsOur findings indicate that benzene and 2-ethyl-phthalate activate AhR/AIP expression and stimulate proliferation in normal rat pituitary cells. This study is the first demonstration that pollutants can induce normal pituitary cells to proliferate and provides a link between epidemiological and genomic findings in pituitary tumors.

Pituitary tumor transforming gene-1 in non-small cell lung cancer: Clinicopathological and immunohistochemical analysis.

Pituitary tumor transforming gene-1 (PTTG1) is a novel oncogene and overexpressed in a wide variety of human cancers. However, the clinical and prognostic significance of PTTG1 in non-small cell lung cancer (NSCLC) is still unknown. The expression status of PTTG1 in NSCLC at the publicly available GEO databases (GSE19804) was observed. The mRNA and protein expression of PTTG1 in NSCLC tissues and cell lines was detected by qRT-PCR and Western blot, and the association between PTTG1 expression and clinicopathological factors was analyzed by immunohistochemistry. In our Results, PTTG1 was one of genes overexpressed in NCSLC samples compared with paired adjacent normal lung samples in microarray data (GSE19804). PTTG1 mRNA and protein expressions were increased in NSCLC tissues and cell lines. PTTG1 protein expression was correlated with malignant status and poor prognosis of NSCLC patients. In conclusion, PTTG1 is correlated with NSCLC progression and as an independent poor prognostic factor in NSCLC patients.

Integrated in silico-in vitro characterization, identification and disruption of the intermolecular interaction between SH3 domain-containing protein kinases and human pituitary tumor-transforming gene 1.

The human pituitary tumor-transforming gene-1 (hPTTG1) has been found to be overexpressed in various cancers. Accumulated evidences implicate that some of protein kinases can specifically recognize two PXXP motifs at hPTTG1 C-terminus through their Src homology (SH3) domain and then phosphorylate the protein by their catalytic domain. Here, we integrate in silico analysis and in vitro assay to characterize the intermolecular interaction between the two hPTTG1 motif peptides 161LGPPSPVK168 (M1P) and 168KMPSPPWE175 (M2P) and the SH3 domains of Ser/Thr-specific protein kinases MAP3K and PI3K. It is identified that the two peptides bind to MAP3K SH3 domain with a moderate affinity, but cannot form stable complexes with PI3K SH3 domain. Long time scale molecular dynamics (MD) simulations reveal that the M1P peptide can fold into a standard poly-proline II helix that is bound in the peptide-binding pocket of MAP3K SH3 domain, while the M2P peptide gradually moves out of the pocket during the simulations and finally forms a weak, transient encounter complex with the domain. All these suggest that the MAP3K M1P site is a potential interacting partner of MAP3K SH3 domain, which may mediate the intermolecular recognition between hPTTG1 and MAP3K.

PTTG1 Levels Are Predictive of Saracatinib Sensitivity in Ovarian Cancer Cell Lines.

Src kinase is recognized as a key target for molecular cancer therapy. However, methods to efficiently select patients responsive to Src inhibitors are lacking. We explored the sensitivity of ovarian cancer cell lines to the Src kinase inhibitor saracatinib to identify predictive markers of drug sensitivity using gene microarrays. Pituitary tumor transforming gene 1 (PTTG1) was selected as a potential biomarker as mRNA levels were correlated with saracatinib resistance, as well as higher PTTG1 protein expression. PTTG1 expression was correlated with proliferation, cell division, and mitosis in ovarian cancer tissues data sets. In sensitive cell lines, saracatinib treatment decreased PTTG1 and fibroblast growth factor 2 (FGF2) protein levels. Downregulating PTTG1 by siRNAs increased saracatinib sensitivity in two resistant cell lines. Our results indicate PTTG1 may be a valuable biomarker in ovarian cancer to predict sensitivity to saracatinib, and could form the basis of a targeted prospective saracatinib trial for ovarian cancer.